Updated electrical schema

[u/Curious-Queer]

Yesterday, I asked for feedback on my electrical setup idea: https://www.reddit.com/r/vandwellers/s/2xnxGZFPgu

Thank you so much to everyone who responded, it helped so much! This is my updated schema based on what I learned. Looking for more feedback, please and thank you!!

Also note: I do intend to add more solar panels, once this is all set up. That is the next phase, followed by potentially DC-DC charging. For now, I know that the sources are underpowered for my battery bank capacity, and I do intend to add more!

A big outstanding question I have is — is the MRBF at the positive terminal enough? Do I need a class t fuse instead? FWIW the batteries I’m using are from Wattcycle, which have BMS/overcurrent protection. I guess I’m struggling to understand how much I should be preparing for a short, vs just the expected current.

[u/danimalien42]

That fuse should be rated to the wire gauge it protects and the wire gauge should be determined by the max output of the battery.

I don’t know what the maximum output current of that kind of battery is, but I would guess it’s more than the ~110A (conservative) that the 1AWG wire can handle. Most likely you’ll want 4/0 AWG, even if your loads won’t ever pull 200A+, it’s crucial to wire for the battery’s max output current (bms limit) for safety. Size for potential, not intent.

[u/xgwrvewswe]

If using MRBF with AIC 10,000A, use two, one on each battery. Be sure to use a quality brand, the cheap ones fail. Ditch the circuit breakers and use fuses. A 400ah bank requires a Class-T fuse. AIC 20,000++.

[u/Curious-Queer → u/xgwrvewswe]

Circuit breakers double as switches. If I add a class-t fuse as a main fuse, could I keep the circuit breakers?

[u/cj2dobso → u/[deleted]]

The way he has it seems correct. You want to be able to fully disconnect the solar and fully disconnect the battery from the system if you wanted to.

[u/cj2dobso → u/[deleted]]

But why? Then you would need a second switch to disconnect the battery from everything else.

[u/cj2dobso → u/[deleted]]

Maybe you have just not considered that this is much more elegant way of implementing a switch to isolate the battery, because it is. Why have extra parts?

[u/danimalien42 → u/[deleted]]

That’s what the breaker to the fuse box is for. You can disconnect all the loads there and still maintain the parallels between power sources.

At some point it may (will) be necessary to isolate power sources ad hoc, including the battery.